Preoperative left ventricular systolic dysfunction correlates with the adverse postoperative consequences of annular-papillary disconnection in the course of mitral valve replacement for stenosis

Background and aims of the study: Preservation of chordae tendineae helps maintain ventricular performance in patients having surgery for mitral regurgitation. The importance of chordal integrity in patients with rheumatic mitral stenosis is unknown. The purpose of this study was to determine the influence of chordal preservation on left ventricular function following relief of rheumatic mitral stenosis. Methods: A total of 142 patients with mitral stenosis had balloon valvulotomy (group 1, n = 63), surgical commissurotomy (group 2, n = 33) or mitral valve replacement (group 3, n = 46). Chordae were resected in all group 3 patients. Left ventricular dimension in end-diastole (LVEDD), end-systole (LVESD) and fractional shortening (FS) were measured at baseline and at a mean interval of 11 +/- 3 months post intervention. Results: At one year, FS increased in groups 1 and 2, but decreased in group 3 (+11.5%, +9%, -6.1%, p<0.005 for group 3 versus groups 1 and 2). A borderline significant increase in LVEDD was seen in group 1 compared with groups 2 and 3 (11%, 5%, 4% respectively, p = 0.05). Differences in FS at follow up were due mainly to diametrically opposite changes in LVESD in the subgroup of patients with baseline left ventricular dysfunction (-1.9%, 0%, +9.8%, p<0.005 for group 3 versus groups 1 and 2). Conclusions: Deterioration of left ventricular function only in patients having mitral valve replacement indicates chordal resection as a putative mechanism. The results of this study suggest that chordal preservation is particularly important in patients with mitral stenosis who have depressed preoperative left ventricular systolic function.